German medical and precision parts manufacturer Böhm just released two new model cars, both powered by an engine that's seriously old school — a Stirling air engine. Not only are they amazingly detailed, but these models can actually drive around, completely without electricity.

The patent for the Stirling air engine goes back to 1816. It was supposed to be a rival to the steam engine, but safer boilers, smaller internal combustion engines and electric motors rendered it obsolete.